Measured liquid dispenser



I March 11, 1969 R. G. RUTHERFORD MEASURED LIQUID DISPENSER Sheet 1 of 3Filed May 25. 1966 INVENTOR. RUSSELL G. RUTH ERFORD March 11, 1969 R. e.RUTHERFORD 3,431,953

MEASURED LIQUID DI SPENSER Filed May 25, 1966 Sheet 2 of 5 g El LQ 'MMINVENTOR. RUSSELLIT. RUTHERFORD March 1969 R. e. RUTHERFORD 3,431,953

MEASURED LIQUID DISPENSER Filed May 25. 1966 Sheet 3 of 5 FIG. 6

m VENTOR. RUSSELL .G.RUTHERFORD United States Patent 3,431,953 MEASUREDLIQUID DISPENSER Russell G. Rutherford, RR. 6, Hutchins Park, Rockford,Ill. 61103 Filed May 25, 1966, Ser. No. 552,803 US. Cl. 141361 12 ClaimsInt. Cl. B65b 1/04, 3/00; B67c 3/00 ABSTRACT OF THE DISCLOSURE Adischarge pipe, with a downwardly directed outer end serving as a nozzledisposed over a can or the like to receive a measured amount of liquid,is connected with the discharge port of a pump cylinder, whose intakeport has a stand-pipe extending downwardly into a small tank thatcontains the liquid at a constant level by reason of float control,there being an overhead supply tank delivering the liquid to the smalltank. An air operated piston in an air cylinder behind the pump cylinderoperates the piston of the pump cylinder once per can as aspring-pressed arm that controls an air valve for the air cylinder isswung in one direction by a can fed past it and the arm thereafterreturns to normal position under spring pressure. The discharge ofliquid from the pipe is regulated by a manually adjustable valve toavoid splatter, this being possible by virtue of the operation of thepump piston under air pressure. A pair of check valves seating inwardlyin the discharge pipe and another pair of check valves seating outwardlyin the intake port and its related stand-pipe cut off the liquiddischarge positively at the end of each discharge even if one of a pairof valves fails to seat fully, thus assuring exactly the same amount ofliquid being dispensed in every operation.

This invention relates to a measured liquid dispenser which, whilespecially designed for use in canning plants to dispense brine in anaccurately measured amount into each can as it is being fed to thefiller in a canning line and constructed to assure continuous operationproperly in such humid environments where electrical components wouldnot be at all satisfactory, making air operation the ultimate inreliability, and requiring operation as fast as the can fillers, even onlines handling up to 360 cans per minute, is not limited to thatspecific application, inasmuch as any brines, syrups, or solutions maybe dispensed and the amount dispensed at each operation is variable tosuit practically any requirement that may arise.

The versatility of the present dispenser in the dispensing of anyliquid, water-like or syrup-like, containing ingredients in canned foodproducts, or even liquids containing soft undissolved solids insuspension, is best emphasized by listing below typical materials thatcan be dispensed:

Ascorbic acid Artificial coloring Barbecue sauce Bean sauce Beef gravyBenzoate of soda Broth Butter Butter sauce Calcium in tomato juiceCalcium cyclamate Chicken fat Citric acid Clam juice Concentratedflavors Cottonseed oil Dill brine Fumaric acid Sauces Tomato brineSeasonings Tomato puree Soya bean oil Tomato sauce Spice oils VinegarSpiced syrups Water Syrups Salient features of the dispenser are:

(1) It is fully automatic in that the unit offers the all importantno-can, no-fill feature;

(2) It is easy to take apart for cleaning and servicing;

(3) A constant level liquid tank is in one assembly with and below theliquid cylinder, liquid being supplied to it through a level controlmechanism on the liquid tank from an overhead gravity supply tank,thereby erasing any likelihood of any variation in the volume dispensedper stroke by reason of change of level in the liquid tank from whichthe liquid is pumped in each dispensing operation;

(4) A manually operated volume control adjustment at one end of the aircylinder accurately predetermines the intake stroke of the air pistonand accordingly of the liquid piston 50 that infinite adjustment ofvolume of liquid dispensed is made possible, and, once the desiredadjustment is obtained, a lock-nut on the adjusting screw can betightened to eliminate any likelihood of alteration accidentally orotherwise,

(5) A trip valve for controlling the operation of the dispenser has anarm oscillated in one direction once per can as they are fed intoposition under the dispenser nozzle, this arm being returned to initialposition after the can passes by spring pressure on the valve plunger byreason of engagement thereon of a finger provided on said arm, wherebyto shut off air to the air cylinder automatically and thus eliminate anylikelihood of any liquid being dispensed in the absence of a can toreceive it, and

(6) A shut-ofl valve in the discharge line to the nozzle is adjustableto regulate discharge and prevent splatter, regulation of the movementof the pistons being made possible by the operation with compressed air.

The invention is illustrated in the accompanying drawings, in which-FIG. 1 is a perspective view showing a typical brine dispensinginstallation using the measured liquid dispenser of my invention;

FIG. 2 is a longitudinal vertical section through said dispenser,omittting the float mechanism seen in FIGS. 3 and FIG. 3 is across-section on the broken line 3-3 of FIG. 2;

FIG. 4 is a horizontal section on the line 44 of FIG.

FIG. 5 is a view partly in section and partly in elevation of the tripvalve shown on a smaller scale in FIG.

FIG. 6 is a section on line 66 of FIG. 3, showing the rest of thedispenser in side elevation, and

FIG. 7 is a sectional detail on the line 7--7 of FIG. 3.

The same reference numerals are applied to corresponding partsthroughout the views.

Referring to the drawings and at first mainly to FIG. 1, the referencenumeral 9 designates the measured liquid dispenser of my inventiongenerally, which is shown set adjacent a filler 10 in a canning plantand having cans 11 delivered to the filler one by one from a table 12 byan indexing rotor 13, the indexing movement of rotor 13 being timed withthe indexing movement of the filler 10 so that in the pausesbetweenthese indexing movements the foremost can 11 disposed in the stationbelow the nozzle 14 will receive its measured amount of brine or otherliquid as indicated at 15 from the nozzle 14, the can being then movedout of the way and to the filler 10 to position another can in that samestation. The cans are conveyed to the filler in any suitable way from asupply source for final discharge down a chute 16 leading to the table12, so that there will always be another can ready to receive the brineor other liquid from the nozzle 14. Should there be a failure of supplyof cans for any reason, the trip valve 17, which is operatedautomatically by the oscillation of the arm 18 against the resistance ofa tension spring or rubber band 19 by abutment of the foremost can withthe arm 18, as shown in FIG. 1, will automatically cut off thedispensing of the brine or other liquid and presumably the filling meansfor filler will be automatically shut ofl at the same time. Compressedair for operating the dispenser 9 is delivered to the trip valve 17through a flexible hose 20 from a pipe 21 connected to the canning plantair supply system, a gauge 22 at the point of connection of hose 20 withpipe 21 indicating the air pressure to the operator so that, in startingup, if there is not sufficient air pressure indicated by the gauge 22 tooperate the dispenser 9, the operator can stop the feeding of cans 11 tothe filler 10 until the right pressure is indicated. A handle is shownat 23 to operate an air shut-off valve 24 provided on the back of thegauge 22. With each retracting movement of the arm 18 under action ofspring 19, air is delivered, as shown best in FIG. 2, from the tripvalve 17 through a flexible hose 25 connected to the forward end of theair cylinder 26 to force the piston 27 therein to the rear, and, byvirtue of its rod connection 28 with the piston 29 working in the liquidcylinder 30, pump a measured amount of brine or other liquid from thecon stant level liquid tank 31 into the cylinder 30, so that when theforemost can 11 engages and moves the arm 18 forwardly against theaction of the spring 19 this measured amount of brine or other liquidwill be discharged from the cylinder through the nozzle 14 by reason ofair being discharged through the flexible tube 32 to the rear end of theair cylinder 26 to force the piston 27 forwardly and with it piston 29in cylinder 30 on the discharge stroke. Hose 25 serves as an exhaustline during the forward movement of piston 27, and hose 32 serves as anexhaust line during the rearward movement of piston 27.

The brine or other liquid being dispensed is supplied from a largeoverhead tank OT by gravity through a downwardly extending flexible hose33 to the constant level liquid tank 31 disposed directly under andconnected to cylinder 30. The hose 33 has its lower discharge endconnected to a supply valve 34 at 35 (see FIG. 4) and the brine or otherliquid is conducted through bore 36 into the liquid tank 31 through anend opening 37 in the valve body and a registering opening 38 in theside wall of the tank, the flow being controlled by an air operatedshut-off valve 39 reciprocated by a piston 40 working in cylinder 41,compressed air for operating the piston being delivered from air supplyhose 20 through the end connection 42 from a hose 43 extending to thefloat controlled valve 44 provided on one side of the constant levelliquid tank 31. A float 45 rigidly secured to a bell-crank lever 46pivoted at 47 in the upper portion of the tank 31 on one side thereofoperates the valve 44 downwardly to close the valve 39 when the desiredlevel is attained in the tank 31. For such operation, the lever 46 hasan arm 48 extending through a slot 49 provided in the side wall of thetank. A leaf spring 50 fixed at one end to the body 51 of valve 44normally urges the valve upwardly to its other extreme position in whichair is delivered through hose 43' to the cylinder 41 on the other sideof piston 40 to open valve 39 for delivery of brine or other liquid totank 31 by gravity from the higher level supply tank OT.

The manually operated volume control adjustment provided by the screw 52at one end of the air cylinder 26 for accurately predetermining thelength of the intake stroke of the air piston 27 and accordinglypredetermining the stroke of the liquid piston 29 so that infiniteadjustment of volume of liquid dispensed is made possible follows, ingeneral, the teaching of my Patent 3,142,258, but, in the presentconstruction, the piston rod 28 has an extension 28' extending from theair cylinder 26 for abutment at its outer end with the screw 52 outsidethe air cylinder, the cross-head 53, in which the screw 52 is threaded,as indicated at 54, being rigidly mounted on the end of the air cylinder26 on two parallel bolts 55. A lock-nut 56 threaded on the adjustingscrew 52 can be tightened against the cross-head 53 after the screw 52has been properly adjusted, whereby to maintain the adjustment andeliminate any likelihood of alteration of the adjustment, accidentally,or otherwise.

The pump and tank assembly forming the present dispenser, designatedgenerally by the reference numeral 9, is unique even though the pumpshown follows generally the disclosure of my earlier patent mentionedabove. The base plate 57 for support of the pump structure serves as thecentral part of a top closure plate for the liquid tank 31, the head 58for one end of the pump structure being loosely held in place on theplate by a cross-bar 59, as will soon appear, the cross-bar beingfastened by screws to the plate. Head 58 has a counterbore 60 in oneside receiving one end of the tube forming the liquid cylinder 30, theother end of which is received in a counter-bore 61 provided in one sideof a plug 62 forming the other end of the liquid cylinder 30. The otherside of plug 62 forms One end of the air cylinder 26 and is of reduceddiameter, as indicated at 63, and has a telescoping fit in one end ofthe tube forming the air cylinder, the other end also having atelescoping fit on the reduced portion 64 of a plug 65 forming the otherend of the air cylinder 26. A back plate 66, which is fastened by screwsto the plate 57 and to which the plug 65 is secured by means of screws67, has bolts 68 extending through parallel holes provided therein andthrough registering holes in the cross-bar 59 previously mentioned andhead 58, nuts 69 threading on the projecting ends of said bolts wherebynot only to draw all of the parts of the pump assembly tightly togetherin liquid tight and air-tight relationship to one another, and yetpermit the entire assembly to be taken apart fairly easily andthoroughly cleaned to meet all sanitary requirements fully, but alsoutilize the bolts 68 and cross-bar 59 as a means of detachably securingthe head 58 t0 the plate 57. The head 58, tube 30', plug 62, tube 26,plug 65, and back plate 66 are all of polyvinyl chloride or otherplastic material not subject to attack by acids and alkalies, and thesame is true of the two parts forming the piston 29 and its scraper ring70 in the liquid cylinder 30. The metal parts, like the piston rod 28,and the lock-nut 71 and other metal parts coming into contact with theliquids are of stainless steel to resist corrosion. Rubber O-rings areindicated at 72-75 to provide liquid-tight joints at opposite ends ofthe liquid cylinder 30 and airtight joints at opposite ends of the aircylinder 26. Other O-rings are indicated at 76 and 77 cooperating withthe shaft 28 and its extension 28 to prevent leakage of air along theshaft at either end of the air cylinder 26, and still another O-ring isindicated at 78 in the piston 29 within the scraper ring 70 to maintainthe ring 70 under radial compression to prevent leakage of liquid pastthe piston 29 in the reciprocation thereof in the liquid cylinder 30.

The liquid tank 31 and the plate 57 and 78' forming the closures for theopposite ends of the tank are also of polyvinyl chloride or otherplastic material, as is also the body of the valve 34 that is fastenedto one side of the cylinder 31 by means of screws 79, so that none ofthese parts are subject to attack by acids and alkalies. Here again, allof the metal parts that come into contact with the liquids, like thescrews 79, are of stainless steel to resist corrosion. The stand-pipe 80extending downwardly into the liquid tank 31 and threaded at its upperend in the bottom of the head 58, as indicated at 81, and the body 82for the check-valve threaded on the lower end of the stand-pipe are alsoof polyvinyl chloride or other suitable plastic material for the samereasons previously indicated. Two parallel plastic side plates 83 and 84suitably fastened by means of screws to the upper end of the liquid tank31 are disposed in close abutment with opposite sides of the generallyrectangular plate 57 to cooperate with said plate to complete a closurefor the upper end of the liquid tank, and a dowel pin 85 mounted on theupper end of the tank fits freely in a vertical hole provided in one endof the plate 57 to locate the plate 57 and hold it against endwisemovement so that a pair of turn type fasteners 87 pivotally secured atone end to the previously mentionesd plates 83 and 84, as at 88, areenough to hold the plate 57 securely in place on top of the liquid tank31 and yet permit the entire pump structure to be removed and replacedwithout any difficulty, as required for easier disassembly andreassembly in cleaning, or for other purposes.

The operation of this measured liquid dispenser should be fairly clearfrom the foregoing description. Assuming a can 11 has just received itscharge of brine or other liquid from nozzle 14 and has been shifted overto the filler by the indexing rotor 13, the arm 18 on the trip valve 17is accordingly pulled back by spring 19, causing the spring pressedfinger 89 to shift the valve plunger 90' of trip valve 17 to its otherextreme position, as seen in FIGS. 2 and 5, to deliver compressed airthrough hose to the forward end of air cylinder 26 and move piston 27 tothe rear, thereby moving piston 29 in the liquid cylinder 30 on itsintake or suction stroke. Under these circumstances, the two stainlesssteel ball check valves 91 and 92 at opposite ends of the stand pipe 80are unseated allowing the brine or other liquid pumped from tank 31through the stand-pipe 80 to flow into the liquid cylinder 30 throughthe port 93 in the plug 58, the other stainless steel ball check valve94 controlling flow between the passage 95 that leads from the cylinder30 and the passage 96 that leads out to the plastic nozzle 14, throughplastic pipe 97, being closed under atmospheric pressure. Then, as soonas the next can 11 engages the arm 18 and moves it forwardly to shiftthe valve 90' to its other extreme position against the action of thespring 19, air is delivered through tube 32 to the rear end of aircylinder 26 moving the piston 27 and piston 29 forward on the dischargestroke, check valves 91 and 92 being closed under pressure, and checkvalve 94 being opened so as to allow the measured amount of liquid to bedispensed through nozzle 14. Another stainless steel ball check valve 98in the plastic swivel fitting 99 cooperates with check valve 94 atopposite ends of the discharge line in the same way as the check valves91 and 92 at opposite ends of the intake line to insure stoppage of floweven if one of the two check valves operating in tandem fails to closedue to some solid particle lodging between the ball and its seat. Ahand-operable all plastic, shut-off valve 100 is provided in thedischarge line, as shown. This valve serves also to reduce (flow if andwhen the liquid being dispensed would otherwise splatter when it hitsthe bottom of the cam 11, such regulation in discharge being a furtheradvantage obtained by the use of compressed air for operating thedispenser. Obviously, if the last can 11 available is shifted from table12 to filler 10, leaving the arm 18 in the retracted position, to whichit is operated by spring 19, as mentioned before, there will be nofurther discharge of brine or other liquid being dispensed, because thedischarge stroke of pistons 29 and 27 requires the forward oscillationagain of the arm 18 by the next can. For any protracted shutdown of thedispenser, the operator will close the shutoff valve 100 to preventseepage of the liquid to and consequent drippage from the nozzle 14.After any protracted shut-down, the operator should after opening valve100 swing the nozzle 14 on its swivel 99 to an out of the way positionand put the dispenser 9 through a few operations by hand manipulation ofthe arm 18 to be sure that the device is operating correctly. In thatway, there is eliminated any likelihood of one or more cans 11 notreceiving the same predetermined amount of brine or other liquid beingdispensed. The hand-operable all plastic, drain valve 101 on the bottomof the liquid tank 31 enables draining all of the liquid from the tankwhenever the dispenser 9 is to be cleaned and whenever it is to bechanged from dispensing of one liquid to dispensing another.

It is obvious that the valve plunger of trip valve 17 can be removed forcleaning or replacement by merely throwing finger 89 over dead-center toan opposite extreme position. The plunger 44 in body 51 is also easilyremovable and replaceable by removal of the screw securing the returnspring 50 to body 51. In both cases, the bore from which the plunger isremoved is then open from end to end for easy cleaning.

It is believed the foregoing description conveys a good understanding ofthe objects and advantages of my invention. The appended claims havebeen drawn to cover all legitimate modifications and adaptations.

I claim:

1. In combination in a measured liquid dispenser, a single actionreciprocating type pump comprising a pump cylinder and a pump pistonreciprocable therein, a small liquid tank directly under and in a fixedclose relation to one end of said pump cylinder in which an intake portand a discharge port are provided, a vertical standpipe extendingdownwardly from the intake port into said tank and having an outwardlyseating check valve therein, a discharge pipe extending from thedischarge port having an inwardly seating check valve therein andterminating in a downwardly directed discharge nozzle in spaced relationto said tank, an upper level large liquid supply tank delivering liquidby gravity to said small liquid tank, float operable means controllingdelivery of liquid from said upper level large supply tank so as tomaintain a constant level of liquid in said small liquid tank regardlessof appreciable changes in level of liquid in said upper level largesupply tank, an air cylinder in fixed coaxial relation to said pumpcylinder and having a piston reciprocable therein which is connected ina fixed spaced relation to said pump piston and has a rod extendingtherefrom and from the end of said air cylinder remote from said pumpcylinder to measure the back-up stroke of said air piston andaccordingly of said pump piston so as to predetermine the amount ofliquid pumped per back-up stroke and subsequently discharged from saidnozzle per forward stroke, a source of compressed air supply, valvemeans communicating therewith controlling the delivery and exhausting ofair to and from opposite ends of said air cylinder, and a manuallyadjustable abutment in an adjustable fixed spaced relation to said aircylinder and arranged for. engagement by the aforesaid rod to vary andpredetermine the liquid dispensed per operation of said dispenser, thevalve means controlling the delivery and exhaust of air to and fromopposite ends of said air cylinder including an arm spring-pressed toone extreme position corresponding to the suction stroke of the pistonin the pump cylinder, said arm being movable'automatically by acontainer as one is positioned under the discharge nozzle to receive theliquid dispensed, whereby a predetermined amount of liquid is dischargedinto it, the arm returning immediately thereafter under spring pressureto its ini tial position to be moved again by the next container.

2. The combination set forth in claim 1, including a manually adjustableflow valve in the discharge pipe, the adjustment of which regulates thedischarge of the liquid into the container so as to avoid splatter, suchregulation being made possible by the operation of the piston in the aircylinder by compressed air.

3. The combination as set forth in claim 1 including a flow regulatingvalve in the discharge pipe to reduce the rate of discharge enough toavoid splatter, such operation being made possible by the operation ofthe piston in the air cylinder by compressed air.

4. The combination as set forth in claim 1, in which the float operablemeans controlling delivery of liquid from the upper level large liquidsupply tank to the lower level small liquid tank includes a reciprocableshut-off valve between the two tanks operable by air operated means, anda valve operable in one direction by spring means and in the oppositedirection by float, said last named valve controlling delivery of air tothe aforesaid air operated means, whereby said shut-off valve is movedto closed position by fioat operation of the other valve and to openposition by spring operation of said other valve.

5. The combination as set forth in claim 1 including a second outwardlyseating check valve operable in tan dem with the check valve in saidstand pipe whereby to insure successful shut-off of communicationbetween said small liquid tank and said pump cylinder in the dischargestroke in the event of failure of one of said check valves to seatfully, the other check valve then serving to fully closed said pipe.

6. The combination as set forth in claim 1 including a second inwardlyseating check valve operable in tandem with the check valve in saiddischarge pipe whereby to insure successful shut-off of cmmunicationbetween said small liquid tank and said discharge nozzle in the suctionstroke in the event of failure of one of said check valves to seatfully, the other check valve then serving to fully close said pipe.

7. In combination in a measured liquid dispenser, a single actionreciprocating type pump comprising a pump cylinder and a pump pistonreciprocable therein, one end of said pump cylinder having an intakeport and a discharge port provided therein, a discharge pipe extendingfrom the discharge port having an inwardly seating check valve thereinand terminating in a downwardly directed discharge nozzle, an inlet pipeextending from the intake port and having an outwardly seating checkvalve therein, constant level liquid supply means communicating with theinlet pipe, an air cylinder in fixed coaxial relation to said pumpcylinder and having a piston reciprocable therein which is connected ina fixed spaced relation to said pump piston, manually adjustable stopmeans measuring the backup stroke of said air and pump pistons topredetermine the amount of liquid pumped per back-up stroke andsubsequently discharged from said nozzle per forward stroke, a source ofcompressed air supply, and valve means communicating with said sourcecontrolling the delivery and exhausting of air to and from opposite endsof said air cylinder and including an arm springpressed to one extremeposition corresponding to the suction stroke of the piston in the pumpcylinder, said arm being movable automatically by a container as one ispositioned under the discharge nozzle to receive liquid dispensedtherefrom, whereby a predetermined amount of liquid is discharged intoit, the arm returning immediately thereafter under spring pressure toits initial position to be moved again by the next container.

8. The combination as set forth in claim 7 including a a manuallyadjustable fiow valve in the discharge pipe, the adjustment of whichregulates the discharge of the liquid into the container so as to avoidsplatter, such regulation being made possible by the operation of thepiston in the air cylinder by compressed air.

9. The combination as set forth in claim 7 including a flow regulatingvalve in the discharge pipe to reduce the rate of discharge enough toavoid splatter, such operation being made possible by the operation ofthe piston in the air cylinder by compressed air.

10. The combination as set forth in claim 7 including two closure plugsfixed on the remote ends of said pump and air cylinders, a third closureplug between and common to the two cylinders having its opposite endsfixed in the adjoining ends thereof to maintain their coaxialrelationship, the last mentioned plug having an axial hole providedtherein through which a rod connecting the air and pump pistons extends,one of the first mentioned two closure plugs being substantiallyrectangular to serve as a mounting block, another substantiallyrectangular mounting block fixed to the other of said first two closureplugs, a supporting base parallel to said cylinders, means for securingone of said mounting blocks to said supportmg base, bolts extending inparallel relation to said cylinders passing through holes in one of saidmounting blocks and through registering holes in the other of saidmounting blocks and having nuts threaded on the outer ends thereof whichwhen tightened serve to draw the mounting blocks together compressingthe inner ends of the two cylinders against opposite sides of the thirdclosure plug common to the two cylinders While pressing the first twoplugs firmly onto the outer ends of said two cylinders, the constantlevel liquid supply means comprising an open top liquid tank the opentop of which is partially covered by said supporting base, the inletpipe extending downwardly from the mounting block abutting one end ofthe pump cylinder to provide communication through said pipe between theinlet port of said pump cylinder and the lower port1on of said tank, twocover plates in spaced parallel relationship to one another on oppositesides of said base secured to the open top of said tank to complete theclosing thereof, and means detachably securing said supporting basebetween said cover plates.

11. A device as set forth in the last claim 10 wherein the lastmentioned means comprises turn fasteners pivoted on said cover plates onopposite sides ofsaid base and swxngable to a position over said base,the top of which lies substantially flush with the top of said coverplates.

12 A device as set forth in claim 10 wherein the last mentioned meanscomprises turn fasteners pivoted on said cover plates on opposite sidesof said base and swingable to a position over said base, the top ofwhich lies substantially flush with the top of said cover plates, andmeans for holding the base against endwise movement relative to the opentop of said tank.

References Cited UNITED STATES PATENTS 1,339,237 5/1920 Thompson 222-382X 2,388,662 11/1945 Anderson et al. 3,120,241 2/1964 Parks 137-4133,190,507 6/1965 MacMillin 222-383 3,231,136 1/1966 Rotter et al 222-334X 3,353,537 11/1967 Knox et al 222334'X FOREIGN PATENTS 813,365 5/1959Great Britain.

SAMUEL ROTHBERG, Primary Examiner. E. I. EARLS, Assistant Examiner.

U.S. CL. X.R.

